At times it is desirable to provide a thin layer of a material on the surface of a substrate. This can be accomplished by providing a mixture of the material to be spread on the surface of the substrate with water. The spreading of the material is generally assisted by addition of a surfactant to the aqueous mixture to reduce the interfacial tension between the water and the substrate.
Application of aqueous agricultural pesticide formulations to plant materials and particularly food crop materials has special requirements. When the material to be spread on the substrate is an insoluble solid or an insoluble oily solid or liquid substance, a surfactant is generally added to the oily or insoluble material and water so that a suspension or emulsion can be formed.
Alkyl polyglycosides are known to be excellent surfactants for assisting in forming a mixture of water insoluble materials and water. In particular, organic polyglycosides are particularly useful as adjuvants for pesticidal materials (see U.S. Pat. No. 4,888,325, and Statutory Invention Registration H 303). However, the organic polyglycosides which are the most effective in forming mixtures of the water soluble materials and water are generally materials which have poor wetting characteristics. That is, the organic polyglycosides which have the most favorable characteristics for forming uniform mixtures and suspensions are not the most effective in reducing the interfacial tension between the mixture and the substrate to which it is applied.